That looks like a lack of oxygen. 

Courtesy of CNN:

Senate Majority Leader Mitch McConnell did not answer questions about his health Thursday, only saying there were “no concerns” after reporters asked him about what appeared to be bruises and bandages on his hands in recent days.

“Of course not,” McConnell told reporters in the Capitol when asked if he had any health issues people should know about.

McConnell, who is up for reelection, later said there were “no concerns” when asked directly by CNN about the apparent bruises or if he had any other problems.

The 78-year-old did not respond when asked if he was being treated by a doctor. An aide to McConnell also declined to provide any additional details when asked multiple times about the majority leader’s health.

I am not a doctor but it does not require one to see that something is definitely wrong with McConnell. 

I would suggest that it might be bruising from having an IV needle stuck in your hand, but the fact that both hands are so completely discolored makes it seem an unlikely explanation. 

What I do know is that Kentucky voters should be told if he is really sick.